Cardiac Anatomy and Physiology Notes

Cardiovascular System Overview

• The cardiovascular (CV) system circulates blood to and from tissues, meeting the body's metabolic needs by:

  • Delivering oxygen and nutrients.

  • Removing waste products.

• The CV system comprises:

  • The heart (primary organ).

  • The pulmonary circulatory system.

  • The systemic circulatory system.

• The heart acts as the driving force (pump) for the entire system, ensuring continuous blood circulation.

• The heart is a two-sided pump: the right heart and the left heart.

Right Heart and Pulmonary Circulation

• The right heart is associated with the pulmonary circulatory system.

• Characteristics of the right heart:

  • Low-pressure system.

  • Low resistance.

  • Low oxygen saturation (O2 sat rate of 75%).

• Deoxygenated blood returns to the right heart via the venous system. This blood is:

  • Depleted of oxygen.

  • Burdened with carbon dioxide.

  • Venous and blue in color.

• The right heart pumps deoxygenated blood to the lungs, where:

  • Carbon dioxide is exchanged for oxygen.

  • Oxygen is acquired during inhalation.

  • Carbon dioxide is excreted during exhalation.

• Oxygenated blood then travels through the pulmonary circulatory system and returns to the left heart via the four pulmonary veins.

Pulmonary Artery Pressure (PAP)

• PAP is the pressure within the pulmonary arteries.

• Normal systolic PAP (SPAP) at rest: 15-25 mmHg.

• Elevated SPAP:

  • Greater than 25 mmHg at rest or greater than 30 mmHg with exercise signifies pulmonary hypertension (PH).

Pulmonary Capillary Wedge Pressure (PCWP)

• PCWP is the pressure measured when a pulmonary catheter with an inflated balloon is wedged into a pulmonary artery branch.

• Normal PCWP: 2-12 mmHg.

• PCWP is an indirect measurement of left atrial pressure.

Define PAP: Pulmonary Arterial Pressure

Define BP: Blood Pressure: The force exerted by circulating blood on the walls of blood vessels, typically measured in millimeters of mercury (mmHg) and expressed as systolic over diastolic pressure.

Define MAP: Mean Arterial Pressure, calculated as the average pressure in a patient's arteries during one cardiac cycle, and is a critical indicator of perfusion.